Mercury And Other Heavy Metals In Fishes From Xiaolangdi Reservoir And Health Risk Assessment

Fish is an important source of food for humans,the nutritional benefits of fish are mainly due to the content of high-quality of protein and high content of two kinds of omega-3 polyunsaturated fatty acids:eicosapentaenoic acid(EPA)and docosahexaenoic acid(DHA),Which have probed to have protective effects in prebenting coronary heart disease,reducing arrhythmias and thrombosis.Since 2002, Since the diet is the main toute of human exposure to heavy metals and fish constitute such an important part of human diet, it is not surprising that the quality and safety aspects of fish are of particular interest.Six fish species were sampled from Xiaolangdi Reservoir, a newly built reservoir located in Henan Province. Total mercury(THg) and methylmercury(Me Hg) contents in the fish muscle tissue were determined using acid digestion-purge and trap-cold vapor atomic fluorescence spectrometry(CVAFS) and KOH/methanol digestion-aqueous phase ethylation-purge and trap-gas chromatography-CVAFS methods, respectively. THg in the fish muscle tissue varied from 31.6 ng/g to 210 ng/g and Me Hg varied from 20.0 ng/g to 194 ng/g. Piscivores and omnivores had higher Hg contents than herbivores. Mercury contents in carp decreased with fish size. For the other fishes, the opposite trend was observed, although the correlation scattered. Mercury contents in the muscle tissue of fish samples could meet the requirement of national standard. However, they were relatively high in comparison to previously studies in other geographic regions. Thus it was suggested that sensitive populations should pay attention to the consumption amount of fish species including bighead, carp and yellow-head catfish.Other heavy metals(As,Cd,Mn,Cu,Zn) contents accumulated in muscle were determined using Inductively coupled plasma mass spectrometry(ICP-MS). Results show that only the contents of other As in muscle tissue of Hypophthalm--ichthysmolitrx and Megalobrama amblycephala are over the national standard. Compared with previously studies in other geographic regions, fisher in Xiaolangdi Reservoir’ heavy metals contents are lower except the upper reaches of Yangtze River and lake of Bhopal; only the contents of non-essential heavy metal in omnivorous fish of Hypophthalmichthys nobilis show a highly significant positive relationships with fish length, just like correlational research others generally appeared to be negative with fish length; the relation between different essential heavy metals generally showed positive, but the relation between essential heavy metals and non-essential heavy metal generally showed negative, especially the essential heavy metal of Mn, we found that Mn has a positive relationship with essential heavy metals and negative with non-essential heavy metals; estimation of non-carcinogenic and carcinogenic health risks by the target hazard quotient and target carcinogenic risk,established by the US Environmental Protection Agency,suggests that the heath risk is low from heavy metal to human being, the major risk contributor is Hg, so as to sensitive crowd such as nursing mothers and young children should restrict their fish consumption, fishes in Xiaolangdi Reservoir has a heigh enrichment capacity of Hg, the enrichment factor of As was lowest in all heavy metals.